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OSU Extension

College of Food, Agricultural, and Environmental Sciences

April 23, 2019 - 8:42am --

Farm Machinery Roadway Laws

            Spring has arrived and another growing season has started.  In an agricultural county like Wayne County, it also signals the start of more farm machinery and equipment on roadways.  Today’s column draws on information from the OSU Extension Agricultural and Resource Law Program, specifically an Ag Law Blog March 26, 2019 post ( and an OSU Extension Law Bulletin publication entitled “Rules of the Road: Navigating Ohio Roadway Laws for Farm Machinery.  

The Oho Revised Code (ORC) defines farm machinery to include all machines and tools used in agriculture to plant, harvest, and transport agricultural products.  Roadway laws outline requirements for signage, lighting, weight limitations, farm machinery dimensions and movement/travel restrictions.  With regard to signage, farm machinery that travels at 25 mph or less must have a slow moving vehicle (SMV) emblem.  The SMV emblem must be visible at 500 feet from the rear of the vehicle.  Any vehicle designed to travel in excess of 25 mph must display a speed identification symbol (SIS) in addition to the SMV emblem.  The SIS must also be visible at a 500-foot distance from the vehicle and displays the maximum possible speed of the vehicle.

Lighting is an important component of roadway safety for farm machinery.  From sunset to sunrise, in conditions of low visibility, or anytime there is precipitation, multi-wheel agricultural tractors of model year 2001 or earlier must have reflectors and illuminated amber lamps.  The ORC says “… the extreme left and right projections of the tractor are indicated by flashing lamps displaying amber light, visible to the front and the rear, by amber reflectors, all visible to the front, and by red reflectors, all visible to the rear.”  The ORC says that multi-wheeled tractors of model year 2002 and later “shall be equipped with and display markings and illuminated lamps that meet or exceed the lighting, illumination, and marking standards and specifications that are applicable to that type of farm machinery for the unit's model year specified in the American society of agricultural engineers standard ANSI/ASAE S279.11 APR01, or any subsequent revisions of that standard.”

According to the Extension Rules of the Road Law Bulletin, “Farm trucks or machinery carrying farm commodities such as livestock, bulk milk, corn, soybeans, tobacco, and wheat are allowed to surpass the general weight limits by 7.5%. This exception is not applicable in February or March, or on interstate highways or highways, roads, or bridges that have reduced maximum weights.”  There are a number of factors that define the general weight limits on roadways.  Quoting the Law Bulletin publication again, “the gross weight of a vehicle with pneumatic tires cannot be greater than 80,000 pounds. For a vehicle with solid tires, the overall weight cannot be greater than 80% of the weight allowed for a pneumatic-tired vehicle.”  If manure, turf, sod, silage, chips, sawdust, mulch, bark, pulpwood, biomass or firewood is hauled; those vehicles are allowed to surpass the general weight limits by 7.5% with no time of year restrictions.

As farm machinery has increased in size, moving along roadways presents challenges to traffic safety and questions are raised regarding legal limits for width, length and height.  Ohio law states that vehicles are not allowed to exceed 102 inches in width, 50 feet in length, or thirteen feet 6 inches in height.  A commercial tractor-semitrailer combination cannot exceed 53 feet in length.  However, farm machinery/equipment that are driven or self-propelled are generally exempted from these limitations.  The Extension Ag Law Bulletin says, “The Ohio Department of Transportation (ODOT) has a policy that interprets this farm machinery exemption. According to ODOT, farm machinery and equipment that is self-propelled or towed falls under the dimension exemption. Farm machinery that is hauled or transported is not exempt from dimension limits.”

There are roadway conditions the limit or restrict the movement of farm machinery/equipment.  These are generally referred to as traffic control devices and include official signs, signals, flaggers, or markings on or near a roadway.  An example is a sign that prohibits farm machinery on a specified stretch of road.  Those traffic devices may, at times, also change weight and dimension requirements on a road and they take precedent over the general weight and dimension exemptions.  Finally, be aware that farm machinery is not allowed on a freeway unless otherwise directed by a police officer.

More information about roadway laws for farm machinery is contained in the Extension Law Bulletin on this topic, available from a link in the Ag law blog post mentioned at the beginning of this article, or contact the Wayne County Extension office at 330-264-8722 if you need a hard copy.


Rory Lewandowski is an OSU Extension Agriculture & Natural Resources Educator and may be reached at 330-264-8722.

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